Heat exchangers such as air cooled heat exchangers (ACHEs) and other heat exchangers operating continuously and often at elevated temperatures, sometimes develop leaks in heat exchange tubes or at junctions of ends of heat exchange tubes with a tubesheet or at junctions of tube plugs in plugsheets. During maintenance, cleaning, inspection, repair and/or upgrade functions, forcible removal of tube plugs often results in serious damage to threads in plugsheets and/or tubes. This damage to threaded surfaces occurs often due to galling of adjacent contacting threaded surfaces where surface material is damaged or even removed.
Prior art includes various tube plugs with internal ducts for fluid sealant as listed below; however, none indicate any awareness of the problem or present solution for damaged threads in plugsheet and/or in heat exchange tube apertures in ACHEs in remote locations with normal repair apparatus being unavailable and a severe need for a quick and feasible solution to avoid lengthy and costly shutdowns: U.S. Pat. Nos. 3,240,379; 3,434,743; 3,472,301; 4,114,654; 5,249,899; 6,588,999; 6,604,899; 6,896,462; 6,902,366; 8,439,220; 2004/0109738; and JP 1993-087488.